You can reinstall ld-elf.so.1 by rebuilding it from the FreeBSD source code.

You do not need to touch elf. You need to upgrade software depending on libxcb.so.1 by relinking them against ibxcb.so.2 -- you would know this if you read the UPDATING file before you updated libxcb. It is possible to say use ibxcb.so.2 whenever ibxcb.so.1 is asked for, but you do not want to do this; the question you've asked explains why.

In short, it appears you upgraded libxcb -- and did not upgrade everything that requires the "old version", which was very well documented in the UPDATING file like so: